The art of producing a PH neutral sanitizer in the form of sodium hypochlororite by the use of a diluted solution of sodium chloride in conjunction with a electrolytic cell is well known in the art. Also, similarly silver and copper ions for aligodynamic sterilization has been in existence for sometime. In most cases, this electrolytic equipment is located out of the pool within the piping requiring continuous pump operation or floating on top of the pool limiting its operating life as batteries are required for the power source. Since many restrictions apply and costs of installation are high, no great popularity has been achieved by the public for this type of pool purifier.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention however, the following U.S. patents were considered related:
______________________________________ PATENT NO. INVENTOR ISSUED ______________________________________ 4,790,923 Stillman 13 December 1988 4,472,256 Hilbig 18 September 1984 4,337,136 Dalhgren 29 June 1982 4,193,858 King 18 March 1980 4,100,052 Stillman 11 July 1978 3,835,020 Galneder 10 September 1974 3,766,045 Itakura, etal 16 October 1973 3,669,857 Kirkham, etal 13 June 1972 3,305,472 Oldershaw, etal 21 February 1967 ______________________________________
Stillman in '923 teaches an electrolytic cell installed in the water outlet pipe through which less than the entire flow of water is directed. Stillman utilizes electrical conductive bars embedded in a cell body serving as terminals. To minimize leakage, Stillman either shortens the terminal electrode; uses an insulative cap; or uses a combination of both. The cell is made such that the edging electrode plates are partially encased in an insulative chemical or the terminal electrodes are shortened to prevent current leakage between plates. This method of construction reduces the active surface area on the terminal electrodes, thus increasing the current density. Higher current density adversely affects electrode life with virtually all electrode materials. This is especially important on the terminal electrodes of a bipolar cell.
Dahlegren approaches the problem of purification using silver and copper ions using a pair of electrodes formed of silver-copper alloy extending from a floating container. A battery provides the electrical energy through a timer switch reversing the current as required to reduce erosion of one or the other electrodes. No modification to an existing pool is required.
Stillman in '052 installs an electrolytic cell in the piping of a fluid system to generate halogen directly from a solution containing a very low salt concentration allowing placement in existing as well as new facilities. The cell includes planar electrode plates attached parallel across the entire cross sectional area of an enclosure. The cell operation requires constant flow of fluid to p event the buildup of hydrogen gas.
Galneder again introduces a flow-through electrolysis chamber. The chamber contains two baffle plates with the electodes mounted therebetween. The electrodes are made of graphite and include an automatic self-adjuster spacer system securing constant maintenance of the initial cell voltage.
Itakura, et al disclose an electrolytic cell for direct electrolysis of sea water to produce hypochlorous acid, hypochlorite or chlorine. Again, the flow of water is through the entire cell. The cathode plates project from a feeding chamber into a electrolyte-exhausting chamber and through a electrolysis chamber such that they act as a funnel making the stream of sea water rise smoothly such that impurities do not adhere on the electrodes.
For background purposes and as indicative of the art to which the invention relates, reference may be made to the following remaining patents found in the search issued to Hilbig, King Kirkham etal and Oldershaw et al.